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Fencer Vulns
medium 6.6

CVE-2021-42550 json

RCE from attacker with configuration edit priviledges through JNDI lookup

published 2021-12-16 4 y ago modified 2026-06-17 4 mo ago also GHSA-668q-qrv7-99fm , EUVD-2021-2454

cvss
6.6
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
4.8%
EPSS 4.8% chance of exploitation in 30 days, percentile 91%
public exploits
0
none known

Summary

In logback version 1.2.7 and prior versions, an attacker with the required privileges to edit configurations files could craft a malicious configuration allowing to execute arbitrary code loaded from LDAP servers.

Patch / fix

  • maven ch.qos.logback:logback-core 1.2.9
  • QOS.ch logback 1.2.9, 1.3.0-alpha11
  • logback Debian 14, Debian 13, Debian 12 1:1.2.8-1

debian advisories DEBIAN-CVE-2021-42550

  • logback Ubuntu Pro 16.04 LTS 1:1.1.3-2ubuntu0.1~esm1
  • logback Ubuntu Pro 18.04 LTS 1:1.2.3-2ubuntu1~18.04.1+esm1
  • logback Ubuntu Pro 20.04 LTS 1:1.2.3-5ubuntu0.1~esm1

ubuntu advisories UBUNTU-CVE-2021-42550

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • foreman satellite utils 6.11, satellite capsule 6.11, satellite 6.11 3.1.1.21-2.el7sat
  • foreman satellite utils 6.11, satellite capsule 6.11, satellite 6.11 3.1.1.21-2.el8sat
  • libsolv satellite capsule 6.11, satellite 6.11 0.7.22-1.el7pc
  • libsolv satellite capsule 6.11, satellite 6.11 0.7.22-1.el8pc
  • candlepin satellite 6.11 4.1.13-1.el7sat
  • candlepin satellite 6.11 4.1.13-1.el8sat
  • satellite satellite utils 6.11, satellite capsule 6.11, satellite 6.11 6.11.0-2.el7sat
  • satellite satellite utils 6.11, satellite capsule 6.11, satellite 6.11 6.11.0-2.el8sat

red hat advisories RHSA-2022:5498

  • xmvn SLES for SAP 15 SP3, SLES for SAP 15 SP2, SLES 15 SP3-LTSS +9 more 4.0.0-150200.3.7.1
  • maven SLES for SAP 15 SP3, SLES for SAP 15 SP2, SLES 15 SP3-LTSS +9 more 3.8.6-150200.4.9.8
  • sbt openSUSE Leap 15.4 0.13.18-150200.4.7.8
  • antlr3 openSUSE Leap 15.4 3.5.3-150200.3.11.8
  • minlog SLES for SAP 15 SP3, SLES for SAP 15 SP2, SLES 15 SP3-LTSS +9 more 1.3.1-150200.3.7.8
  • xmvn-mojo SLES for SAP 15 SP3, SLES for SAP 15 SP2, SLES 15 SP3-LTSS +9 more 4.0.0-150200.3.7.8
  • xmvn-tools SLES for SAP 15 SP3, SLES for SAP 15 SP2, SLES 15 SP3-LTSS +9 more 4.0.0-150200.3.7.1
  • antlr3-java openSUSE Leap 15.4, Manager Server Module 4.3 3.5.3-150200.3.11.8

suse advisories SUSE-SU-2023:2097-1

  • libdb Rocky Linux 8 5.3.28-42.el8_4

rocky linux advisories RLSA-2022:5498

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2021-42550 updated cvss 6.6

logback: remote code execution through JNDI call from within its configuration file

  • Red Hat BPM Suite 6 logback-classic
    affected: no fix planned “Out of support scope”
  • Red Hat Integration Camel K 1 logback-classic
    affected: no fix available
  • Red Hat JBoss BRMS 6 logback-classic Red Hat JBoss Fuse 6 logback-classic
    affected: no fix planned “Out of support scope”
  • Red Hat Fuse 7.11
    fixed: vendor fix RHSA-2022:5532
  • Red Hat Satellite 6.11 for RHEL 7 candlepin 4.1.13-1.el7sat Red Hat Satellite 6.11 for RHEL 8 candlepin 4.1.13-1.el8sat
    fixed: vendor fix RHSA-2022:5498
  • Red Hat RHDM 7.12.1
    fixed: vendor fix RHSA-2022:1110
  • Red Hat RHPAM 7.12.1
    fixed: vendor fix RHSA-2022:1108
  • Red Hat Integration Camel Quarkus 1 logback-classic Red Hat Satellite 6.11 for RHEL 7 tfm 7.0-1.el7sat, gofer 2.12.5-7.el7sat, katello 4.3.0-3.el7sat, libsolv 0.7.22-1.el7pc, libcomps 0.1.18-1.el7pc, libsolv0 0.6.34-4.el7sat, +637 more Red Hat Satellite 6.11 for RHEL 8 libdb 5.3.28-42.el8_4, katello 4.3.0-3.el8sat, libsolv 0.7.22-1.el8pc, libcomps 0.1.18-1.el8pc, python-idna 3.3-1.el8pc, python-pbr 5.6.0-1.el8pc, +628 more
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

cisa ICSA-22-314-03 updated cvss 6.6

Siemens SINEC Network Management System Logback Component

Facts from CISA's republication of the vendor's own advisory (CSAF); the linked advisory is the authoritative source. CISA notification · csaf

Exploit prediction

4.77% chance of exploitation in the next 30 days, higher than 91% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • jira.qos.ch https://jira.qos.ch/browse/LOGBACK-1591 referenced PoC, tagged "exploit" by a source, unverified
  • github.com https://github.com/cn-panda/logbackRceDemo referenced PoC, tagged "exploit" by a source, unverified
  • packetstormsecurity.com http://packetstormsecurity.com/files/167794/Open-Xchange-App-Suite-7.10.x-Cross-Site-Scripting-Command-Injection.html referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 3.1 6.6 CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:H/I:H/A:H
NVD 3.1 6.6 CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:H/I:H/A:H
NVD 2.0 8.5 AV:N/AC:M/Au:S/C:C/I:C/A:C
GitHub 3.1 6.6 CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:H/I:H/A:H

Affected packages

ecosystem package affected fixed in
maven ch.qos.logback:logback-core
<1.2.9
1.2.9

Affected products

  • QOS.ch logback

Classification

Weakness
  • CWE-502 Deserialization of Untrusted Data

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.